In this paper, we fabricated periodic Si micro-bump structure, and sensory evaluation of tactile feeling of roughness and frictional resistance with human finger was conducted with paired comparison method. In addition, friction coefficient between the micro-bump array and an artificial urethane finger model that mimics human fingertip was evaluated. The samples had various bump sizes with width of 20∼600 µm and space of 20 µm. The space between the bumps (20 µm) was decided so that finger skin cannot enter the grooves. The result of sensory evaluation showed that rough feeling was increased with decreasing the micro bump size from 600 µm to 50 µm due to the edge effects of micro bump. The friction resistance feeling was influenced by contact area between the skin and bump surface. In addition, the friction resistance feeling was strong when the micro bump size was 50 µm. Also, the stick-slip phenomenon was strongly observed in the frictional measurement using artificial finger model.

Enzymes which have potential to detect specific chemical substances are important molecules in drug discovery, food and medical diagnosis. The most powerful method for evaluation of enzyme activity is fluorescence technique. However, there is a problem that the fluorescence methods such as Fluorescence Resonance Energy Transfer (FRET) need development of fluorescence molecules. In our previous study, we have developed the arrayed electrochemical sensors for oxidation current measurement of redox mediator in the reaction of oxidoreductase which oxidizes mediator with catalysis. In this study, we fabricated the electrochemical array sensor to measure reduction current of oxidized mediator. The sensor is based on an internal photoelectric effect. The concentration dependency of observed current on single sensor element shows monotonic dependency over range 10 mM - 1 µM and 10 mM - 100 nM for [Fe(CN)₆]^3-/4- and [Fe(CN)₆]^3-, respectively. Furthermore, the concentration dependency of observed current on two sensor elements shows a relation of monotonic dependency over range 10 mM - 100 nM on two elements.

Poly (3,4-ethylenedioxythiophene) (PEDOT) conductive polymer and polyvinylidene difluoride (PVDF) piezoelectric polymer thin films were formed by dip-coating method. The relationship between drawing speed and film thickness was experimentally investigated. Dip-coated PEDOT and PVDF thin films were characterized and confirmed that both had surely worked as electrode and piezoelectric film of a flexible power generation element, respectively. Using dip-coating method, these thin films were successfully formed on 3D surface of a bellows shaped spring made of silicone rubber.

The Internet of Things (IoT) is an infrastructure for connecting a broad range of devices to the Internet and other IoT-ready devices. Data accumulated by IoT devices can benefit users by analyzing these data using artificial intelligence techniques. Therefore, the IoT and IoT-ready devices can improve the quality of life of users within a smart city, a next-generation city also designed to decrease energy consumption. In snow-covered areas within such a smart city, measuring snow depth is important, but conventional techniques for measuring snow depth are unsuitable for the IoT because devices would need to be placed at numerous survey spots and conventional commercial devices are usually ultrasonic or laser-based, which are extremely expensive for IoT applications.

Considering these limitations, we propose a novel IoT device to measure snow depth using inexpensive sensors, including temperature/humidity, illuminance, and electrical conductivity (EC) sensors. To the best of our knowledge, this study is the first report on devices that measure snow depth electrically. As first reports of electrically snow detection, we reported detecting snow by investigating the reduction of electric resistance in EC sensor output values. In fabricated IoT devices, we are able to measure snow depth by multiple placed low-cost EC sensors along the vertical direction. The unit cost of a fabricated device is $65, approximately 1/30 and 1/66 cheaper than that of conventional ultrasonic and laser-based devices, respectively.